The goal of this study is to determine the optimal sensor or combination of sensors to measure tidal volume in stable intubated neonates and infants during normal breathing, motion and airway obstruction to improve apnea detection. In addition to existing monitoring systems, we attach two ECG electrodes each on both the ribcage and the abdomen, one inductive belt each on both the ribcage and the abdomen, and a pneumotachometer to the existing endotracheal tube. Data is recorded for one hour and experiments are simultaneously videotaped.